1. Field of the Invention
This invention relates to a magnetic head for recording/reproducing information on a magnetic medium, and more particularly to a floppy head which is incorporated in a floppy disk drive device used, for instance, as an external memory of a computer.
2. Discussion of the Background
As a magnetic head used for the floppy disk drive of an external memory of a computer, a magnetic head 31 of laminate type shown in FIGS. 4 and 5 is typically used. The magnetic head 31 has a core lamination structure 32 as a magnetic head core which is held from both sides with a pair of sliders 34A and 34B made of non-magnetic ceramics and the like. The components of the magnetic head 31 are fixed integrally with a known resin, glass, and the like. The core structure 32 comprises a pair of erase heads 36A and 36B laminated on both sides of a relatively wide recording/reproducing head 35. The bottoms of these sliders 34A and 34B, and the core lamination structure 32 form a sliding surface opposing a magnetic recording medium 46 such as a floppy disk, and a pair of sliding rails 37A and 37B are formed on the bottoms thereof on both sides of a groove 45 extending in the advance direction 47 of the medium 46. The core lamination structure 32 is exposed on one of the rails 37A at the same plane. As shown in FIG. 5, each of the recording/reproducing head 35 and the erase heads 36A and 36B of the core lamination structure 32 comprises a magnetic core member 38 formed with an I-type core piece and an L-type core piece and a nonmagnetic reinforcing member 39 of ceramics and the like which is fixed on the side of said I-type core piece and doubles as a spacer. The magnetic cores 38 of the pair of erase heads 36A and 36B are situated at a position upstream the magnetic core 38 of the recording/reproducing head 35 in the advance direction 47 of the magnetic recording medium 46. With said I-type core piece and L-type core piece, a magnetic gap Gr for recording/reproducing is formed on the magnetic core member 38 of the head 35, and magnetic gaps Ge for erasing are formed on respective magnetic cores 38 of the erase heads 36A and 36B. The gap Gr is separated from the gaps Ge by an interval distance L in the advance direction 47 of the medium 46. As the distance L between the gaps determines the characteristics of a magnetic head 31 at the stage of manufacture, it is most critical to control the distance L.
In the manufacture of magnetic heads of laminated type mentioned above, the method shown in FIG. 6 is usually employed to position the recording/reproducing head 35, erase heads 36A and 36B of the core lamination structure 32 and sliders 34A and 34B in order to set the interval distance L between the gaps. According to this method, bottom surfaces of the recording/reproducing head 35, erase heads 36A and 36B forming the core structure 32 and sliders 34A and 34B are aligned on a reference surface (not shown) by means of a jig, and pressed perpendicularly to the laminated surfaces, from the direction shown with an arrow Y in the figure. Then, the core structure 32 and the sliders 34A and 34B are held from both sides thereof by a fixed jig 43A and a movable jig 43B, and pressed in the direction marked with an arrow X by the movable jig 43B so as to align one end each of the respective components with a reference surface 50 of the jig 43A. As the end surfaces of the recording/reproducing head 35 and of erase heads 36A and 36B in the advance direction 47 of the magnetic medium 46 are formed on a plane perpendicular to the lamination of the core structure 32, the core components are positioned by contacting the respective end surfaces with the reference alignment surface 50 of the fixed jig 43A. Subsequently, the core lamination structure 32 and the sliders 34A and 34B are fixed integrally with one another with resin or glass. A gimbal 40 made of a thin elastic metal plate and the like is fixed on the upper surface of the magnetic head 31 as shown in FIG. 4. A coil 41 is mounted on the core lamination structure 32 which projects through the gimbal 40. A back core 42 is provided on the recording/ reproducing head 35 projecting from the coil 41. The gimbal 40 is connected to a drive (not shown) for changing the position of said magnetic head 31 relative to the magnetic recording medium.
In the magnetic head positioned as above, the interval distance between the gaps determined at the time of manufacture of the magnetic head is critical to the characteristics thereof. Therefore, the respective components should be positioned at a higher precision so as to set the interval distance L between the gaps precisely. As described above, the distance L between the gaps is determined by contacting one end each of the respective component heads 35, 36A and 36B with the reference alignment surface 50 of the jig. But when a foreign matter such as dust or a torn piece of the core should enter between the end surfaces of the respective components and said reference surface, said end surfaces would deviate from said reference surface, and as a result, the distance L between the gaps becomes different from the predetermined value to inconveniently lower the dimensional precision of said core lamination structure, cause defects, and decrease the yield.